Excessive fertilization of lakes causes the quality of fish produced to:

Concept

Eutrophication occurs when excessive nitrogen and phosphorus stimulate dense algal growth in a water body. As algae die, microbial decomposition consumes dissolved oxygen; some blooms also release toxins or damage fish gills.

Application

1. Excess fertilizer enters the lake, increasing nutrient concentrations and stimulating algal growth.

2. Dense blooms block light, while decomposition of dead algae consumes dissolved oxygen; some blooms also clog gills or release toxins.

3. Fish then experience hypoxia, physiological stress, reduced growth or reproduction, disease susceptibility, and sometimes death, so their quality is impaired.

Contrast

• Remain unchanged ignores the changes in oxygen, habitat, and fish health caused by excessive nutrient loading.

• Improve confuses a possible rise in primary productivity with sustained fish health.

• First improve and then be impaired describes a possible progression of productivity, whereas the stem asks about fish quality under excessive fertilization.

Result

Therefore, excessive fertilization impairs the quality of fish produced.